What if the Coptic result also included our religious holidays and the Hijri months?

The people of Islam have their own history, by which they date their feasts, acts of worship, and transactions. Hajj, fasting, waiting periods ('iddah), breastfeeding, and zakat are all legally bound by the lunar months, as Allah Almighty says: "They ask you, [O Muhammad], about the new moons. Say, 'They are measurements of time for the people and for Hajj.'" Therefore, a Muslim should not deviate from the Hijri calendar and the lunar months.